Wintery blast expected to hit much of the country this week

Temperatures are set to plummet as the worst winter storm of the year sweeps the country.

Bitterly cold southerlies are expected right across the country, with wind chill and heavy rain cause for concern, according to Metservice.

"High impact severe weather" is expected from Wednesday through to Friday, with Metservice warning of flooding, severe gales and heavy rain. The extreme weather may cause transport problems and stress to livestock.

The cold front will move up from the south from Tuesday, and is expected to deepen across the east of the North Island on Wednesday, continuing north on Thursday.

The cold front is expected to bring significant snow above 200m across many parts of the South Island.

Coldest overnight temperatures during the week:

Invercargill -3degC on Friday

Gore -5degC on Friday

Queenstown -5degC on Friday

Wanaka -4degC on Tuesday

Mt Cook -8degC on Friday

Alexandra -5degC on Monday

Timaru -2degC on Friday

Christchurch -1degC on Friday

Hokitika 0degC on Friday

MetService says people should wrap up warm ahead of the wintery weather blast this week, with conditions not expecting to ease until the weekend.